From: Milton Aupperle <milton@outcastsoft.com>

Date: March 24, 2008 3:39:11 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] IR filter with a DMK color .AS camera?


Hi Duane;


On 24-Mar-08, at 3:04 PM, Duane wrote:

I'm pretty far along in this game to be asking about simple rules, but this one's got me 

wondering...


I forget the exact model... but I've got a DMK Color camera with the .AS after it.


A DMK is a mono camera. Maybe you mean DBK or DFK?


According to the TIS web site:


http://www.astronomycameras.com/en/products/


For .AS camera,s the following rules apply for what filters shipped with the camera.


A DMK  is a mono camera and it has no IR filter.


A DBK is a bayer color camera and has no IR filter.


A DFK is color camera (delivers bayer or YUV video) and has an IR Filter.


Do I need to use the IR filter on planets and the Moon?


For Lunar yes - for planetary generally yes.


The moon reflects a lot of IR light and that comes into focus at a different focal length than visible light. So an IR filter or a filter that restricts the light band width (i.e. a Red filter or a Green Color Filter) will help give you a better sharper image.


For planets, especially the dimmer ones beyond Mars it's less clear whether or not it's as important.


I didn't think I needed to with color web cams (like the Fire-i) but I was wondering about the 

.AS (I thought that was just a firmware change but not sure).


The Fire - I have no IR filters. Once you remove the lens, your CCD is naked as the IR filter is on the back part of the lens.


I've tried it both ways and didn't see much difference, but then again the nights I was out 

didn't present me with the best skies.


It depends on the target.


HTH..


Milton J. Aupperle